package Leetcode;

/**
 * @ Author     ：侯耀祖
 * @ Description：
 */
public class addTwoNumbers {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        ListNode head = null;
        ListNode tail = null;
        int i = 0;
        while (l1 != null || l2 != null){
            int sum = 0;
            int n1 = l1 != null ? l1.val : 0;
            int n2 = l2 != null ? l2.val : 0;
            sum = n1 + n2 + i;
            if (head == null){
                head = tail = new ListNode(sum % 10);
            } else {
                tail.next = new ListNode(sum % 10);
                tail = tail.next;
            }
            i = sum / 10;
            if (l1 != null) {
                l1 = l1.next;
            }
            if (l2 != null) {
                l2 = l2.next;
            }
        }
        if (i > 0){
            tail.next = new ListNode(i);
        }
        return head;
    }
}
